%AArcher, M.D.
%AFeldberg, S.W.
%BOther Information: PBD: 16 Sep 1998; Related Information: In: Encyclopedia of Science and Technology, vp.
%D1998%IMcGraw-Hill, New York, NY (US); Brookhaven National Lab., Upton, NY (US)
%K37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ELECTRIC POTENTIAL; ELECTROMOTIVE FORCE; FREE ENERGY; ELECTROLYTIC CELLS; ELECTRON TRANSFER
%MOSTI ID: 760971
%PMedium: ED; Size: page(s) 12
%TELECTROMOTIVE FORCE, EMF (CELLS)
%Uhttp://www.osti.gov/scitech//servlets/purl/760971-5WjNJO/webviewable/
%XThe voltage or electric potential difference across the terminals of a cell when no current is drawn from it. The emf of a cell is the sum of the electric potential differences (PDs) produced by a separation of charges (electrons or ions) that can occur at each phase boundary (or interface) in the cell. The magnitude of each PD depends on the chemical nature of the two contacting phases. Thus, at the interface between two different metals, some electrons will have moved from the metal with a higher free energy of electrons to the metal with a lower free energy of electrons. The resultant charge separation will produce a PD (just as charge separation produces a voltage across a capacitor) that, at equilibrium, exactly opposes further electron flow. Similarly, PDs can be produced when electrons partition across a metal/solution interface or metal/solid interface, and when ions partition across a solution/membrane/solution interface.
%ZOther Information: PBD: 16 Sep 1998; Related Information: In: Encyclopedia of Science and Technology, vp.
%0Miscellaneous
%@BNL--65847; KC030101; R&D Project: AS002CSD; Other: KC030101; TRN: AH200035%%46
United StatesR&D Project: AS002CSD; Other: KC030101; TRN: AH200035%%46Tue Feb 05 03:52:19 EST 2008McGraw-Hill, 121 Avenue of America, New York, NY 10011 (US); OSTI as DE00760971BNL; EDB-00:097101English